Lifestyle

5 Signs Doctors Say You May Have Prediabetes Without Knowing It

By Erica Coleman · July 14, 2026

More than 115 million American adults have prediabetes. Eight in ten of them have no idea.

That’s not a rounding error — it’s a defining feature of the condition. According to the CDC, prediabetes typically produces no clear symptoms, which is exactly why it goes undetected until it has already progressed to something more serious. Left untreated, prediabetes can become type 2 diabetes within five years. It also raises the risk of heart disease and stroke on its own, independent of whether diabetes develops.

The encouraging part: prediabetes is reversible. Losing a modest amount of weight and increasing physical activity can cut the risk of developing type 2 diabetes in half, the CDC reports. But you can only act on information you have — and most people with prediabetes are never tested because they assume they’d feel something if something were wrong.

Here’s what doctors say to watch for, and what’s actually worth bringing up with your physician.

Persistent fatigue that doesn’t improve with sleep. When blood sugar is consistently elevated, the body’s ability to convert glucose into energy becomes impaired. Cells don’t get the fuel they need, and the result is fatigue that lingers regardless of how much rest you get. It’s easy to chalk this up to stress, aging, or poor sleep — which is exactly why it goes unrecognized as a blood sugar signal.

Increased thirst and more frequent urination. Excess sugar in the bloodstream draws fluid from the body’s tissues as the kidneys work harder to filter it out. That fluid loss triggers thirst, which leads to more drinking, which leads to more frequent urination. The cycle is subtle enough that most people don’t notice it as a pattern until it’s pointed out.

Darkened skin in the creases of the body. This one is specific and often overlooked. A condition called acanthosis nigricans — darkened, velvety patches of skin that appear in the neck, armpits, or groin — is a known marker of insulin resistance, the underlying mechanism that drives prediabetes. It’s not a rash or a hygiene issue; it’s the skin responding to elevated insulin levels.

Blurry vision. High blood sugar draws fluid from the lenses of the eyes, temporarily affecting their ability to focus. This tends to come and go rather than being constant, which makes it easy to dismiss as eyestrain or the need for a new glasses prescription. Persistent or recurring blurry vision without a clear optical explanation is worth mentioning to a doctor.

Slow-healing cuts or frequent infections. Elevated blood sugar impairs circulation and reduces the body’s ability to fight infection. A cut that takes longer than expected to heal, or minor infections that keep coming back, can both signal that blood sugar is affecting the body’s basic repair mechanisms.

None of these signs are conclusive on their own — fatigue and blurry vision have dozens of explanations, and many people will have one or two of these without any blood sugar issue at all. But the combination of multiple symptoms, particularly in someone over 45 with a family history of diabetes, excess weight, or a sedentary lifestyle, is enough to ask a doctor for a fasting blood sugar test or an A1C. Both are routine blood draws. Neither requires fasting for the A1C. And if the result comes back in the prediabetes range — a fasting glucose between 100 and 125 mg/dL, or an A1C between 5.7% and 6.4% — that’s not a diagnosis of diabetes. It’s a window.

The CDC’s National Diabetes Prevention Program offers structured lifestyle programs specifically designed for people with prediabetes, available through a network of community organizations and online providers. Many are covered by insurance, and some are free.